Following are a number of back-translations as well as a sample translation for translators of Jeremiah 50:7:

• Kupsabiny: “All the people that they encountered fought against them,
  so that their enemies went around saying,
  ‘We have no mistake/guilt,
  because they have sinned against God
  whom their forefathers trusted/put their hope in!’” (Source: Kupsabiny Back Translation)
• Hiligaynon: “They are-being-attacked by the-(ones) who saw them. Their enemies are-saying, ‘They have-sinned against the LORD who is their true rest and the hope of their ancestors, so we have no sin in our attacking them.’” (Source: Hiligaynon Back Translation)